Name: compact lens-less digital holographic microscope for mems inspection and characterization
Uploaded: 2016-07-05T15:00:00
Description: Watch this Scientific Journal Video about Compact Lens-less Digital Holographic Microscope for MEMS Inspection and Characterization at JoVE.com

The authors have no acknowledgements.

1. Indledende Forberedelse af Measurement Bemærk: Prøver til brug for forsøget er et MEMS elektrode. Guldet elektroder er fremstillet på en silicium wafer hjælp lift off proces. Prøven er en 18 mm x 18 mm wafer med periodiske strukturer (elektroder) med 1 mm periode <ol><li> Log ind logbogen, inden du bruger systemet. </li><li> Tænd for computeren, LASER og oversættelse fase magt. </li><li> Placer MEMS elektrode / mikro-membran prøve. <ol><li> Anbring MEMS prøve i midten af ​​holderen prøve ved ...

<ol>
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I denne anmeldelse, giver vi en protokol til præcist genvinde den kvantitative morfologi forskellige MEMS enheder ved hjælp af et kompakt system bygger på digital holografi. MEMS karakterisering i både statisk og dynamisk tilstand er påvist. Kvantitative 3D-data i en mikro kanal MEMS er opnået. For at validere systemets nøjagtighed, er resultater blevet sammenlignet mellem CDHM og AFM. God aftale er fundet betyder, at digital holografi kan være en pålidelig teknik til 3D-billeder. Resultater indikerer, at syste...

Metrologi af mikro- og nano objekter er af stor betydning for både industrien og forskere. Faktisk miniaturisering af objekter repræsenterer en ny udfordring for optisk metrologi. MEMS (MEMS) er generelt definerede har miniaturiserede elektromekaniske systemer og normalt omfatter komponenter såsom mikro-sensorer, mikro aktuatorer, mikroelektronik og mikrostrukturer. Det har fundet mange anvendelser på forskellige felt som bioteknologi, medicin, kommunikation og sensing 1. For nylig, den stigende kompleksitet samt den gradvise miniaturisering af test objekt funktioner opfordring til udvikling af passende karakteriseringsteknikker til MEMS. Høj overførselshastighed fremstilling af disse komplekse mikrosystemer kræver gennemførelse af avancerede inline måleteknik, at kvantificere karakteristiske parametre og relaterede defekter forårsaget af procesbetingelserne 2. Eksempelvis afvigelsen af ​​geometriske parammetre i en MEMS enhed påvirker systemets egenskaber og skal karakteriseres. Desuden industrien kræver høj opløsning måling ydeevne, såsom fuld tre dimensioner (3D) metrologi, stort felt af udsigt, høj billedbehandling opløsning og real time analyse. Således er det vigtigt at sikre en pålidelig kvalitetskontrol og inspektion proces. Det forudsætter desuden, målesystemet være let gennemførlig på en produktionslinje og dermed relativt kompakt at blive installeret på eksisterende infrastruktur. Holography, som først blev introduceret af Gabor 3, er en teknik, der gør det muligt at inddrive det fulde kvantitative oplysninger af et objekt ved at registrere interferens mellem en reference og et objekt bølge i en lysfølsom medium. Under denne proces kendt som optagelse, er amplituden, fasen og polarisering af et felt lagret i mediet. Derefter objektet bølge felt kan udvindes ved at sende referencestrålen på migdium, en proces kendt som optisk læsning af hologrammet. Da en konventionel detektor kun registrerer intensiteten af ​​bølgen, har holografi været genstand for stor interesse i de sidste halvtreds år, da det giver adgang til yderligere oplysninger om det elektriske felt. Men flere aspekter af konventionel holografi gør det upraktisk for industrielle applikationer. Faktisk lysfølsomme materialer er dyre og optageprocessen kræver generelt en høj grad af stabilitet. Fremskridt i høj opløsning kamera sensorer såsom ladede koblede enheder (CCD) har åbnet en ny tilgang til digital metrologi. En af disse teknikker er kendt som digital holografi 4. I Digital Holography (DH), er hologrammet optaget på et kamera (optagemedie) og numeriske processer bruges til at rekonstruere fase og intensitet oplysninger. Som med konventionel holografi, kan resultatet opnås efter to procedurer: den optagelse og genopbygning, som vist i Figur 1. Men hvis optagelsen ligner konventionel holografi, genopbygningen er kun numerisk 5. Den numeriske genopbygningsprocessen er vist i figur 2. To procedurer er involveret i genopbygningen. For det første er det objekt bølge felt hentet fra hologrammet. Hologrammet multipliceres med en numerisk henvisning bølge at få objektet bølgefront ved hologrammet flyet. For det andet er det komplekse objekt bølgefronten numerisk opformeret til billedplanet. I vores system er dette trin udføres ved hjælp af foldning metode 6. Den rekonstruerede felt opnåede er en kompleks funktion og dermed fase og intensitet kan udvindes tilvejebringe kvantitative højdeoplysninger på objektet af interesse. Evnen til hele felt information opbevaring i holografi metode og brugen af ​​computer-teknologi til hurtig databehandling giver mere fleksibilitet i eksperimentel konfiguration og en betydelig forøgelse af Speed af den eksperimentelle proces, åbner op for nye muligheder for at udvikle DH som et dynamisk metrologisk værktøj for MEMS og mikrosystemer 7,8. Anvendelse af digital holografi i fase kontrast imaging er nu veletableret og blev første gang præsenteret mere end ti år siden 9. Faktisk undersøgelse af mikroskopiske enheder ved at kombinere digital holografi og mikroskopi er udført i mange undersøgelser 10, 11, 12, 13. Adskillige systemer baseret på høj kohærens 14 og lave sammenhæng 15 kilder samt forskellige typer af geometri 13, 16, 17 (på linje, off akse, fælles vej ...) er blevet præsenteret. Endvidere i overensstemmelse digital holografi tidligere har været anvendt i karakterisering af MEMS-indretningen 18, 19. Men disse systemer er generelt vanskelige at gennemføre og pladskrævende, hvilket gør dem uegnede til industriel anvendelse. I denne undersøgelse foreslår vi en kompakt, enkel og linsen frit system baseret på off axis digital holografi stand til tidstro MEMS inspektion og karakterisering. Compact Digital holografiske mikroskop (CDHM) er en linse mindre digitalt holografisk system udviklet og patenteret for at opnå 3D-morfologi af mikro-størrelse spejlende objekter. I vores system, en 10 mW, meget stabile, temperaturkontrolleret diode laser, som fungerer ved 638 nm kobles til en mono-mode fiber. Som vist i figur 3, er den divergerende stråle, der udgår fra fiberen opdelt i en reference og et objekt stråle ved en stråledeler. Henvisningen strålegang omfatter en vippet spejl til at realisere off akse geometri. Objektstrålen er spredt og reflekteret af prøven. De to stråler interfererer på CCD giver hologrammet. Den interferens mønster trykt på billedet kaldes en rumlig luftfartsselskab og tillader inddrivelse af den kvantitative fase oplysninger med kun ét billede. Den numeriske rekonstruktion udføres ved hjælp af en fælles Fouriertransformation og foldning algoritme som stated tidligere. Objektivet-mindre konfiguration har flere fordele gør det attraktivt. Da der ikke anvendes linser, input stråle er en divergerende bølge giver en naturlig geometrisk forstørrelse og dermed forbedre systemets opløsning. Desuden er det gratis aberrationer stødt i typiske optiske systemer. Som det kan ses i figur 3B, kan systemet gøres kompakt (55x75x125 mm 3), let (400 g), og kan således let integreres i industrielle produktionslinjer.

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	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">2 MP Camera</td>
			<td style="width:251px;">Imaging Source</td>
			<td style="width:251px;">DMX 41BU02</td>
			<td style="width:512px;">used to record the hologram. 4.65 microns pixel size</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Motorized X,Y,Z Translation Stage</td>
			<td style="width:251px;">Zaber Technology&#160;</td>
			<td style="width:251px;">TLS28-M</td>
			<td>Holder for the system&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Beam splitter</td>
			<td style="width:251px;">Edmund optics</td>
			<td style="width:251px;">49-003</td>
			<td>Cube Beam splitter. Separate and recombine the object and reference beam</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Laser&#160;</td>
			<td style="width:251px;">Micro Laser Systems, Inc.</td>
			<td>SRT-F635S-20/OSYS</td>
			<td>Diode laser</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Mirror</td>
			<td style="width:251px;">Edmund Optics</td>
			<td style="width:251px;">#43-412-566</td>
			<td>1&#34; Dia. Protected Gold, &#955;/20 Flat Zerodur</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">monomode Fiber</td>
			<td style="width:251px;">Thorlabs</td>
			<td style="width:251px;">S405-XP</td>
			<td style="width:512px;">Single Mode Optical Fiber, 400 - 680 nm, &#216;125 &#181;m Cladding</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Sample holder</td>
			<td style="width:251px;">Edmund Optics</td>
			<td style="width:251px;">#39-930</td>
			<td>Ideal Positioning Platform,&#177;35mm Travel in Both X and Y</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Hotplate</td>
			<td style="width:251px;">Thermolyne Mirak hotplate</td>
			<td style="width:251px;">Barnstead International HP72935-60</td>
			<td>temperature range&#160;&#160; 40-370 &#176;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Holoscope Software</td>
			<td style="width:251px;">d&#39;Optron Pte Ltd</td>
			<td style="width:251px;">NA</td>
			<td>software developed by the NTU researchers&#160;</td>
		</tr>
	</tbody>
</table>

compact lens-less digital holographic microscope for mems inspection and characterization

A micro-electro-mechanical-system (MEMS) is a widely used component in many industries, including energy, biotechnology, medical, communications, and automotive. However, effective inspection and characterization metrology systems are needed to ensure the functional reliability of MEMS. This study presents a system based on digital holography as a tool for MEMS metrology. Digital holography has gained increasing attention in the past 20 years. With the fast development and decreasing cost of sensor arrays, resolution of such systems has increased broadening potential applications. Thus, it has attracted attention from both research and industry sides as a potential reliable tool for industrial metrology. Indeed, by recording the interference pattern between an object beam (which contains sample height information) and a reference beam on a CCD camera, one can retrieve the quantitative phase information of an object. However, most of digital holographic systems are bulky and thus not easy to implement on industry production lines. The novelty of the system presented is that it is lens-less and thus very compact. In this study, it is shown that the Compact Digital Holographic Microscope (CDHM) can be used to evaluate several characteristics typically consider as criteria in MEMS inspections. The surface profiles of MEMS in both static and dynamic conditions are presented. Comparison with AFM is investigated to validate the accuracy of the CDHM.

Den ovenfor beskrevne protokol designet til at inspicere og karakterisere MEMS og Micro enheder ved hjælp CDHM system. I vores system er en mono-mode fiber koblet til en diodelaser opererer ved en 633 nm bølgelængde. På grund af den divergerende stråle konfiguration, er det vigtigt at matche objektstrålen og referencestrålen vej for at opnå et hologram, der kan rekonstrueres. Dette opnås ved omhyggelig lodret positionering af prøven i forhold til systemet. I den beregnede indpa...

Watch this Scientific Journal Video about Compact Lens-less Digital Holographic Microscope for MEMS Inspection and Characterization at JoVE.com

Compact Lens-less Digital Holographic Microscope for MEMS Inspection and Characterization

Vi præsenterer et kompakt refleksion digitalt holografisk systemet (CDHM) for inspektion og karakterisering af MEMS-enheder. En linse-mindre design ved hjælp af en divergerende input bølge giver naturlig geometrisk forstørrelse demonstreres. Både statiske og dynamiske studier præsenteres.

Kompakt Lens-mindre Digital Holografisk Microscope for MEMS Inspektion og karakterisering

A micro-electro-mechanical-system (MEMS) is a widely used component in many industries, including energy, biotechnology, medical, communications, and ...

The overall goal of this procedure is to test micro-electro-mechanical structures to be used in static and dynamic applications using optical full-field measurements with computational and experimental techniques. This method can help answer key questions in the semiconductor industry and more specifically for micro-electro-mechanical system inspection such as the characterization of the mechanical properties of MEMS structures at different stages of manufacturing. The main advantage of this technique is that it is full-field, non-contact, real-time, high-resolution, and it provides a fully quantitative 3D map of the reflective object.The system have been made with no lens and, hence, is really compact. So this method can provide insight into MEMS characterization. It can also be used for wafer inspection or optics reference testing.If set up in a transparent geometry, it is also possible to inspect micro-optics, diffractive optics, or even used for bioimaging. This procedure uses a compact digital holographic microscope, or CDHM, to characterize a micro-electro-mechanical system or MEMS device. For this demonstration, an 11 square millimeter silicon wafer with square gold electrodes positioned every 0.25 millimeters will be characterized.Using tweezers, place the MEMS sample on the sample holder. Adjust the sample holder so that the laser beam targets the electrodes. The largest possible field of view is limited by the camera sensor, and in this case, is 2.3 by 1.8 millimeters.Vertically position the system about 1.5 centimeters from the sample, and proceed with setting up the 3D View software. This package was developed in C+Begin with clicking on the green box icon to select the video imaging device. Choose the DMx 41BU02 imaging source camera in the drop-down menu.Next, under the Device Settings, Select the Y800 Video Format option, and set the capture rate to 15 Frames Per Second. Press OK, and start the camera using the yellow play button. A live video image of the sample should appear.The displayed image should be a defocus image of the sample. Adjust the exposure time and contrast of the image if needed. Now, center the sample as best as possible and access the Settings options.There, set the System Type to Reflection or Transmission. Check that the wavelength of the laser is set to 633 nm, The Pixel size of the camera to 4, 650 nm, and the magnification is times two. Next, select the Convolution Reconstruction algorithm, and set the Reconstruction Distance to 100 mm and the Reconstruction Step to one.The reconstruction distance can be adjusted later to adjust the intensity image to a sharp focus, while the Step parameter indicates how many times the convolution operation is performed to simulate the beam propagation. This parameter can be changed to fine-tune the reconstruction distance in the intensity image. Lastly, under the Post Processing options, set the Unwrapping algorithm to the Quality mapped option.Make sure that the Intensity filter and the Phase filter options are set to None. Then, press OK.Begin with accessing the 3D View software and opening the Fourier spectrum window. If one zero order and two plus one minus one order spectrums do not appear, check that the sample is placed below the red laser beam.The laser reflection can easily be seen from the sample. Now, stop the live measurement mode and select one of the diffracted orders using the filter tool. Select an area large enough to encompass all the frequencies needed for the phase retrieval.Select the SET option to apply the filter. Then, restart the live measurement mode. With the selection made, and imaging live, open the Phase window and make sure that the unwrapped mode is not enabled.Next, adjust the vertical stage to reduce the number of fringes in the phase image so only one or two fringes remain. Let the system adjust after each stage movement. To find the best reconstruction distance, use the auto-focus option.Several refocus steps may be needed to get to the optimal reconstruction distance. Ultimately, the image should become sharp and clear. Fine focus adjustments can be made using the focus slider bar if the auto-focus is not providing the best result.For very fine focus adjustments, the Reconstruction Step can be changed in the settings. With the image prepared, enable the unwrapped mode to see the unwrapped phase image. In the 3D View software, open the 3D image window to see the final image of sample, and use the available image adjustments to observe the result.On the unwrapped phase image, select the ruler icon and draw a line on the area of interest to get a cross-sectional plot in the line plot window. Now, in the line plot window, use the two green line markers to get an approximate height of the object. To arrange the windows for simultaneous viewing, select the Tile Windows option.Surface roughness can also be calculated on the flat part of the sample using MATLAB software. Save the final phase image as a bitmap for further viewing in other software. To prepare the sample for dynamic analysis, position it on the sample stage for analysis.In this case, the sample is a micro diaphragm. Connect the sample electrodes to the crocodile clips of the generator. Following the described procedures, record a hologram of the micro diaphragm at the ambient temperature for reference.Click on the Delta icon to remove the initial phase, and thus only observe deformation. Then, turn on the DC generator and gradually increase the voltage from zero to 12 volts, taking phase map images at every 1 volt increment. Later, using a simple MATLAB code, plot the different phase map deformations into one graph to better observe the total deformation, and characterize the MEMS deformation to electrical loading.A CDHM system was used to characterize a MEMS device as described, using a monomode fiber coupled to a diode laser operating at a 633 nanometer wavelength. The object beam and reference beam path were matched to obtain a hologram image of the MEMS device. The yellow line represents the cross-section location on the sample, and the two green marker lines were used to estimate the sample height.To validate the results of the digital holographic system, an atomic force microscope was used to measure the same structure. A height difference of 2.1 nanometers was found between the atomic force microscope measurement and the CDHM measurement. A MEMS electrode made using a lift-off process is subject to sample morphology variance that needs quantification.Using the described protocol, a def map was made for this purpose. A plot in the other dimension shows that surface roughness of the electrode is also observable using the system. In a dynamic system, with the temperature rising from 50 to 300 degrees Celsius, morphological changes were measured in a micro diaphragm fabricated by bonding a thin-plate onto an SOI wafer sample.This thermal deformation was then summarized in a line plot showing a cross-sectional view of the different deformation states. After watching this video you should have a clear understanding of how to set up the system and carry out morphological studies related to reflective samples such as 3D profile, deformation maps, and surface roughness. Once trained, anyone can use the software and the system so that it can be easily implemented on production chains and operated by technicians.While attempting this procedure, it's important to remember to place the sample at the right distance from the system. This is an important step. And it has a real impact on the final results.After it's development, this technique b-v for researchers in the field of optical and electrical engineering to categorize the behavior of MEMS samples for static and dynamic conditions. Following this procedure, other experiments like observation of resonant mode while your playing high-frequency alternative current or quantifying cantilever deflection can be performed in order to provide a calibration of a packed column MEMS device.

Research

JoVE Journal

Engineering

Compact Quantum Dots for Single-molecule Imaging

Kompakte Quantum Dots for Single-molekyle Imaging

Single-molecule imaging is an important tool for  understanding the mechanisms of biomolecular function and for visualizing the  spatial and temporal ...

Construction of a High Resolution Microscope with Conventional and Holographic Optical Trapping Capabilities

Opførelse af en høj opløsning Mikroskop med konventionelle og Holografisk Optiske fældefangst Capabilities

High resolution microscope systems with optical traps allow for precise manipulation of various refractive objects, such as dielectric beads 1 or cellular ...

Real-Time DC-dynamic Biasing Method for Switching Time Improvement in Severely Underdamped Fringing-field Electrostatic MEMS Actuators

Real-Time DC-dynamisk Prioritering Metode til Switching Time Forbedring Alvorligt Underdamped Fringing-felt Elektrostatiske MEMS aktuatorer

Mechanically underdamped electrostatic fringing-field MEMS actuators are well known for their fast switching operation in response to a unit step input ...

Single Plane Illumination Module and Micro-capillary Approach for a Wide-field Microscope

Single Plane Illumination modul og Micro-kapillær-metoden for en Wide-field mikroskop

A module for light sheet or single plane illumination microscopy (SPIM) is described which is easily adapted to an inverted wide-field microscope and ...

Comprehensive Characterization of Extended Defects in Semiconductor Materials by a Scanning Electron Microscope

Omfattende karakterisering af Extended Fejl i Semiconductor Materials af en Scanning Electron Microscope

Extended defects such as dislocations and grain boundaries have a strong influence on the performance of microelectronic devices and on other applications ...

Fabrication of 3D Carbon Microelectromechanical Systems (C-MEMS)

Fabrication of 3D Carbon Microelectromechanical Systems C-MEMS

Fremstilling af 3D-carbon-mikroelektromekaniske systemer (C-MEMS)

A wide range of carbon sources are available in nature, with a variety of micro-/nanostructure configurations. Here, a novel technique to fabricate long ...

Demonstration of a Hyperlens-integrated Microscope and Super-resolution Imaging

Demonstration af en Hyperlens-integreret mikroskop og super-resolution Imaging

The use of super-resolution imaging to overcome the diffraction limit of conventional microscopy has attracted the interest of researchers in biology and ...

Design and Characterization Methodology for Efficient Wide Range Tunable MEMS Filters

Design og karakterisering metode til effektiv Wide Range afstemmelige MEMS filtre

Here, we demonstrate the advantages of the laser Doppler vibrometer (LDV) over conventional techniques (the network analyzer), as well as the techniques ...

Intermediate Strain Rate Material Characterization with Digital Image Correlation

Mellemliggende stamme sats materielle karakterisering med Digital billed korrelation

The mechanical response of a material under dynamic load is typically different than its behavior under static conditions; therefore, the common ...

Implementation of a Nonlinear Microscope Based on Stimulated Raman Scattering

Gennemførelse af et ikke-lineært mikroskop baseret på stimuleret Raman spredning

Stimulated Raman scattering (SRS) microscopy uses near-infrared excitation light; therefore, it shares many multi-photon microscopic imaging properties. ...